Marine Biogeochemistry

Chemical Oceanography

Chemical oceanography investigates the chemical composition of sea water. Chemical oceanographers study the interactions between organic and inorganic substances and the biological, physical and geological conditions of the ocean. They want to understand how marine chemistry is influenced by physical processes and exchange with the atmosphere, biosphere and geosphere.

Processes, which introduce chemical species into the ocean and those which remove or transform the substances are important targets of marine chemical research. We preferentially investigate the cycling of those elements which are important for biological processes ( eg. carbon, nitrogen, phosphorus, iron,...). The ocean contains each chemical element of our planet either in its pure form or in any kind of chemical compounds either dissolved or particulate. About 50 quadrillion tons (peta tons) of dissolved salts are the most important ingredients in the 96.5% of the global water, stored in the oceans. These salts are mainly sodium chloride, calcium carbonate and -sulphate, potassium sulphate, and magnesium chloride, -sulphate and -bromide. Were it possible to deposit the oceanic salts onto the continents, a layer 166 m high would cover the land surfaces.

Besides the main components of seawater, which strongly dictate its properties, many elements and compounds occur as trace ingredients confering great biogeochemical interest. These constituents often exhibit important biological or chemical functions, which stimulate the specific interests of marine chemistry and chemical oceanography. Sea water contains many gaseous components, which are introduced into the atmosphere or are absorbed from it.

The origin and fate of gases, affecting the atmosphere are a very special element of research therefore. Green house gases, contributing to atmospheric warming, trace gases forming aerosols and those destroying ozone belong to this category.

As chemistry controls and reflects the environment of the ocean-earth-atmosphere system, chemical oceanography has links to all the other disciplines of the GEOMAR. We therefore work in close co-operation with the physical, geological, and biological research units of ocean and earth sciences research.